RAPID: Impacts of Hurricane Maria on tropical forest biogeochemistry: short-term response and long-term trajectory

这项研究将研究飓风玛丽亚对热带森林中有机碳和养分动态的直接影响，以及该森林的溪流，以更好地确定短期影响如何影响森林和水资源在单一和重复干扰后的长期轨迹。飓风玛丽亚导致波多黎各的卢基略实验森林（LEF）内大范围的林冠破坏和土壤表面及河道中的垃圾沉积。了解植物碎屑中的有机碳、磷和氮在其通过土壤和进入溪流的运动过程中（包括与大气的任何交换）如何被改变，对于确定生态系统对干扰的长期反应至关重要。作为该项目的一部分进行的研究将深入了解LEF生态系统的恢复力和抵抗力，该生态系统是美国国家森林系统中El Yunque国家森林的一部分。 PI团队将与波多黎各的科学家和学生密切合作，并促进当地学生和教师的研究需求。研究人员将把项目结果纳入一系列以气候变化对陆地生态系统的影响为中心的演示和推广活动。该项目将促进科学的多样性，支持波多黎各学生担任实验室工作人员，为其他西班牙裔学生和博士后科学家提供培训，并通过外联和辅导活动促进科学领域的两性平等，这项研究利用了预先存在的飓风模拟实验，使研究人员能够测试关于单一和重复飓风扰动对生态系统过程的影响的假设，包括碳和养分通过土壤剖面的生态地球化学转移以及微生物活动对基质可用性和水分条件的反应。 研究小组将量化沉积在土壤上的凋落物数量，测量土壤碳和磷组分，氮矿化，铁物种，铝和土壤剖面，土壤蒸渗仪和溪流中的pH值。将评估微生物活性，同时还靶向与大分子碳水化合物降解以及氮和磷循环相关的基因表达。通过Illumina HiSeq测序的转录数据将被映射到来自预先存在的宏基因组的组装支架，并提供评估基因表达变化的方法。 这项研究将提供第一个飓风影响的综合实验，描述飓风前后的环境条件和土壤深度的地球化学循环，以及单一和重复的干扰。这个小组也将是第一个采用新的分析微生物活性，转录组学，并直接将其与扰动和恢复背景下的地球化学指标联系起来。

This research will study the immediate effects of Hurricane Maria on the dynamics of organic carbon and nutrients in a tropical forest and the streams draining that forest to better determine how short-term impacts affect the long-term trajectory of forest and water resources following single and repeated disturbances. Hurricane Maria led to widespread canopy damage and litter deposition on the soil surface and in stream channels within the Luquillo Experimental Forest (LEF) in Puerto Rico. Understanding how organic carbon, phosphorus, and nitrogen within plant detritus are modified during their movement through soils and into streams, including any exchanges with the atmosphere, is critical to determining long-term ecosystem response to disturbance. The research conducted as part of this project will provide insights into the resilience and resistance of the LEF ecosystem, part of the El Yunque National Forest in the US National Forest System. The PI team will work closely with scientists and students in Puerto Rico and facilitate local student and faculty research needs. The investigators will build the project results into a portfolio of presentations and outreach activities centered on the impacts of climate variability on terrestrial ecosystems. The project will promote diversity in science by supporting Puerto Rican students as laboratory personnel, providing training to other Hispanic students and post-doctoral scientists, and promoting gender equity in science through outreach and mentoring activities.This research makes use of a pre-existing hurricane simulation experiment allowing the researchers to test hypotheses about the effects of single and repeated hurricane disturbance on ecosystem processes, including biogeochemical translocations of carbon and nutrients through soil profiles and microbial activities in response to substrate availability and moisture conditions. The research team will quantify the amount of litter deposited on the soil, measure soil carbon and phosphorus fractions, nitrogen mineralization, iron species, aluminum, and pH in soil profiles, soil lysimeters, and stream water. Microbial activity will be assessed while also targeting gene expression related to macromolecular carbohydrate degradation and nitrogen and phosphorus cycling. Transcript data sequenced via Illumina HiSeq will be mapped to assembled scaffolds from pre-existing metagenomes and provide a means of assessing changes in gene expression. The research will provide the first comprehensive experiment of hurricane effects that characterizes the pre- and post-environmental conditions and biogeochemical cycling with soil depth, and across single and repeated disturbances. This group will also be the first to employ novel analyses of microbial activity, transcriptomics, and link this directly with biogeochemical indices in the context of disturbance and recovery.